Question

body of mass 5kg is moving with 10kgms^-1 momentum .0.2 force acts on it for 10s in the direction of motion.calculate increase in kinetic energy.​

Answer 1

Given,

mass(m) = 5 kg

momentum(p) = mass*velocity = 10 kgm/s

force(f) = 0.2 N

time of force(t) = 10sec.

Solution,

p= m*v = 10 kgm/s

(5 kg)*v = 10 kgm/s

v = (10kgm/s)/5kg

= 2m/s

hence, initial velocity =2m/s (since it was already moving.)

f=ma

0.2N=(5kg)*a

a= (0.2N)/(5kg)

a= 0.04 m/s²

a= (final velocity-initial velocity)/change in time

a= Δv/Δt = (v-u)/Δt

0.04 m/s² = (v-2)/10sec

v= (0.04*10)+2

v = 2.4 m/s

change in kinetic energy (K)= (mv²/2) - (mu²/2)

= (m/2) (v²-u²)

= (5/2) (2.4² - 2²) = 4.4 joule.

this is your answer...

hope it helps 2 you..